Technology on the Move: Recent and Forthcoming Innovations for Tracking Migratory Birds Author(s) :Eli S. Bridge, Kasper Thorup, Melissa S. Bowlin, Phillip B. Chilson, Robert H. Diehl, Renéé W. Flééron, Phillip Hartl, Roland Kays, Jeffrey F. Kelly, W. Douglas Robinson and Martin Wikelski Source: BioScience, 61(9):689-698. 2011. Published By: American Institute of Biological Sciences URL: http://www.bioone.org/doi/full/10.1525/bio.2011.61.9.7
Thsi paper provides a good overview of innovative technologies used for tracking birds such as GPS, cellular netwroks, solar geolocation, radar etc.